Devices for reducing ball impact into ball seats and methods of reducing ball impact into ball seats

ABSTRACT

Seats for receiving a plug member comprise a tubular member having a seat disposed therein and a fluid flow reduction member that reduces the velocity of the fluid flowing through the tubular member as it approaches the seat so as to reduce the impact of the plug member landing on the seat. The fluid flow reduction member may be disposed on a fluid flow reduction device, such as on an inner wall surface of a sleeved insert, or formed in the inner wall surface of the tubular member. The fluid reduction member can comprise one or more longitudinal channels, one or more apertures, or one or more curved-shaped grooves disposed either on the inner wall surface of the tubular member or on a fluid flow reduction device, such as on an inner wall surface of a sleeved insert disposed within the tubular member.

BACKGROUND

1. Field of Invention

The present invention is directed to devices for reducing impact of balls into ball seats for use in oil and gas wells and, in particular, to devices located adjacent to or as part of a ball seat having one or more fluid reduction member for slowing down fluid flowing toward the ball seat so that the ball slows down as it approaches the ball seat.

2. Description of Art

Broadly, ball seats are devices placed within a conduit string or a wellbore through which a fluid is permitted to flow. In some instances it is desired to restrict or prevent flow through the conduit or wellbore so that pressure can build-up within the conduit or wellbore to actuate a downhole tool such as a setting tool to set an anchor or a packer within the conduit or wellbore. Ball seats are used to restrict or prevent such fluid flow by landing or seating a plug or ball on the seat to block flow. Typically, the seat and the ball are formed out of metallic materials such that a rounded portion of the ball lands on a flat surface of the seat. In other embodiments, the seat may have a shape that is reciprocal to the ball, e.g., arcuate to be reciprocally-shaped to the ball.

Although the term ball is used herein to refer to the seats disclosed herein, it is to be understood that the seats may be used in connection with any type of plug or plug member, such as a plug dart. Therefore, except where expressly identified as requiring the plug member or plug to be a ball, it is to be understood that “ball” and “plug” are used herein interchangeably.

SUMMARY OF INVENTION

Broadly, ball seats for receiving a plug member for use in downhole operations in a wellbore comprise a tubular member having an inner wall surface defining a bore. The bore is divided into an upper portion and a lower portion. Generally, the upper portion comprises an upper diameter and the lower portion comprises a smaller lower diameter. A seat is disposed along the inner wall surface between the upper portion and the lower portion so that the seat transitions the inner wall surface from the upper portion to the lower portion. A fluid flow reduction device can be disposed adjacent the ball seat or formed as part of the ball seat. The fluid flow reduction device causes fluid flow toward the seat to decrease as it approaches the seat. As a result, a plug member being carried toward the seat slows down as it approaches the seat. By slowing down, the likelihood that the plug member will impact the seat at a speed that causes damage to the plug member or the seat is reduced. In one particular embodiment, the fluid flow reduction device is disposed above the seat. In another embodiment, the fluid flow reduction device is disposed adjacent, i.e., in contact with, the seat. In still another embodiment, the fluid flow reduction device is form integral, or as a part of, the seat. Moreover, the fluid flow reduction device can comprise one or more longitudinal grooves, one or more curved grooves, or one or more apertures.

In one specific operation of the seat, the seat restricts fluid flow through a conduit disposed within a wellbore when disposed within the conduit. A plug member is dropped down the conduit and is carried by fluid flowing down through the seat. As the fluid approaches the seat, the fluid is forced through one or more fluid flow reduction members disposed on, for example, the inner wall surface of the tubular member or on a fluid flow reduction device disposed in the conduit, such as the inner wall surface of a sleeved insert. As a result, the fluid approaching the seat is slowed, which in turn slows the speed of the plug member approaching the seat such that the plug member is landed on the seat at a speed that is less than the speed at which it was previously approaching the seat before the fluid entered into the one or more fluid flow reduction devices.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a partial cross-sectional side view of one specific embodiment of a seat shown prior to landing a plug member on the seat.

FIG. 2 is a partial cross-sectional view of the seat shown in FIG. 1 with a plug member landed on the seat.

FIG. 3 is a cross-sectional top view of the embodiment shown in FIG. 1, with a plug member landed on the seat.

FIG. 4 is a partial cross-sectional side view of another specific embodiment of a seat shown prior to landing a plug member on the seat.

FIG. 5 is a partial cross-sectional side view of an additional embodiment of a seat shown prior to landing a plug member on the seat.

FIG. 6 is a partial cross-sectional side view of another embodiment of a seat shown prior to landing a plug member on the seat.

While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF INVENTION

Referring to FIGS. 1-3, in one specific embodiment, ball seat 40 comprises tubular member 42 having inner wall surface 44 defining bore 45. Bore 45 is restricted by seat 48. Disposed along inner wall surface 44 of tubular member 42 is fluid flow reduction device 60. As shown in the embodiment of FIGS. 1-3, fluid flow reduction device 60 is an insert comprising a sleeve disposed adjacent and above seat 42. In the embodiment of FIGS. 1-3, fluid flow reduction device 60 comprises one or more fluid flow reduction members, shown as fluid channels 62 disposed along inner wall surface 63. In the embodiment of FIGS. 1-3, fluid flow reduction device 60 comprises a plurality of longitudinal fluid channels or grooves 62 running parallel to longitudinal axis 64 of fluid flow reduction device 60. Although, fluid flow reduction device 60 comprises a plurality of longitudinal fluid channels 62, it is to be understood that fluid flow reduction device 60 can comprise as few as one longitudinal fluid channels 62.

It is to be understood that the apparatuses and methods disclosed herein are considered successful if the plug element, e.g., ball 100 in FIG. 2, is sufficiently in contact with seat 48 to sufficiently restrict fluid flow through seat 48 so that the desired downhole operation can be performed. In other words, a leak-proof seal between the plug element and the seat are not required.

In operation of the specific embodiment shown in FIGS. 1-3, ball seat 40 is disposed within wellbore or a conduit, e.g., a work string (not shown) that is placed into the wellbore (not shown). Connection of ball seat 40 to the conduit can be accomplished through any method or device known in the art, such as threads disposed at the upper and lower ends of ball seat 40. After being disposed at the appropriate location within the wellbore, a plug element, such as ball 100 is transported down the bore of the conduit along with a fluid, such as a completion fluid. As the ball approaches seat 48, the fluid carrying ball 100 is directed through fluid flow reduction device 60. As the embodiment of FIGS. 1-3 comprises fluid flow reduction device 60 having a plurality of longitudinal fluid channels 62, the fluid is directed through each of longitudinal fluid channels 62 as indicated by the arrows shown in FIG. 1. In this arrangement, the fluid is permitted to flow around ball 100 as it approaches seat 48. As a result of the fluid being forced through longitudinal fluid channels 62, the velocity of the fluid flowing through fluid flow reduction device 60 is reduced. The reduction in velocity of the fluid slows down the velocity of ball 100 as it approaches seat 48. Ball 100 then lands on seat 48 to provide the fluid restriction through the conduit so that a downhole operation can be performed. Because each of longitudinal fluid channels 62 is blocked at their lower ends by seat 48, fluid flow through longitudinal fluid channels 62 is restricted after ball 100 is landed on seat 48.

Referring now to FIG. 4, in another embodiment, ball seat 140 comprises fluid flow reduction device 160, shown as an insert in tubular member 42, comprising a sleeve having recess 161 disposed along an outer wall surface 164 and plurality of fluid flow reduction members shown as apertures 162 disposed within inner wall surface 163. Although, fluid flow reduction device 160 comprises a plurality of apertures 162, it is to be understood that fluid flow reduction device 160 can comprise as few as one aperture 162. In addition, each aperture 162 can comprise an opening having a shape or size that is different from the other apertures 162. Thus, each aperture 162 is not required to be a circle. Nor is each aperture 162 required to be identical in size.

Operation of the embodiment shown in FIG. 4 is similar to the operation of the embodiment of FIGS. 1-3 with the difference being that the fluid flow reduction device 160 comprises a plurality of apertures 162 so that the fluid is directed through each of apertures 162 as indicated by the arrows shown in FIG. 4. In particular, the fluid is forced through one or more aperture 162 into recess 161 and then out of recess 161 through another aperture 162. In this arrangement, the fluid is permitted to flow around the plug element (not shown) as it approaches seat 48. As a result of the fluid being forced through apertures 162, the velocity of the fluid flowing through fluid flow reduction device 160 is reduced. The reduction in velocity of the fluid slows down the velocity of the plug element as it approaches seat 48.

With reference to FIG. 5, in an additional embodiment, ball seat 240 comprises fluid flow reduction device 260, shown as an insert in tubular member 42, comprising a sleeve having fluid flow reduction members, shown as curved-shape fluid channel or groove 262 disposed within inner wall surface 263. In the embodiment of FIG. 5, fluid flow reduction device 260 comprises a single curved-shape fluid channel 262 comprising a spiral-shaped fluid channel disposed in inner wall surface 263. Although, fluid flow reduction device 260 comprises a single curved-shaped fluid channel 262, it is to be understood that fluid flow reduction device 260 can comprise more than one curved-shaped fluid channels 262. Further, although the curved-shaped fluid channel 262 is shown as spiral-shaped channel extending from the upper end of fluid flow reduction device 260 to the lower end of fluid flow reduction device 260, it is to be understood that curved-shaped fluid channel 262 is not required to be spiral-shaped and can be truncated in either direction such that curved-shaped fluid channel 262 does not extend to one or both of the upper end and/or lower end of fluid flow reduction device 260.

Operation of the embodiment shown in FIG. 5 is similar to the operation of the embodiment of FIGS. 1-3 with the difference being that the fluid flow reduction device 260 comprises curved-shape fluid channel 262 so that the fluid is directed through curved-shape fluid channel 262 as indicated by the arrow shown in FIG. 5. In this arrangement, the fluid is permitted to flow around the plug element (not shown) as it approaches seat 48. As a result of the fluid being forced through curved-shape fluid channel 262, the velocity of the fluid flowing through fluid flow reduction device 260 is reduced. The reduction in velocity of the fluid slows down the velocity of the plug element as it approaches seat 48.

As illustrated in FIG. 6, in another embodiment ball seat 340 comprises fluid flow reduction device 360, shown as an insert in tubular member 42, comprising a sleeve having a plurality of fluid flow reduction members shown as longitudinal fluid channels or grooves 362 running parallel to longitudinal axis 364 of fluid flow reduction device 360. Longitudinal fluid channels 362 are each shown as being truncated, i.e., as not extending the entire length of fluid flow reduction device 360 from the upper end of fluid flow reduction device 360 to the lower end of fluid flow reduction device 360. Although, fluid flow reduction device 360 comprises a plurality of longitudinal fluid channels 362, it is to be understood that fluid flow reduction device 360 can comprise as few as one longitudinal fluid channels 362. Moreover, although, longitudinal fluid channels 362 shown in FIG. 6 each intersect either the upper end or lower end of fluid flow reduction device 360, it is to be understood that one or more longitudinal fluid channels 362 may not intersect either the upper end or the lower end of fluid flow reduction device 360.

The length and width of each longitudinal fluid channels 362 may be identical. Alternatively, the lengths and widths of each longitudinal fluid channels 362 may differ from one another.

Operation of the embodiment shown in FIG. 6 is similar to the operation of the embodiment of FIGS. 1-3 with the difference being that the fluid flow reduction device 360 comprises a plurality of longitudinal fluid channels 362 disposed in inner wall surface 363. In this arrangement, the fluid is permitted to flow through longitudinal fluid channels 362 around the plug element (not shown) as it approaches seat 48. As a result of the fluid being forced through longitudinal fluid channels 362, the velocity of the fluid flowing through fluid flow reduction device 360 is reduced. The reduction in velocity of the fluid slows down the velocity of the plug element as it approaches seat 48.

Although the ball seats 60, 160, 260, 360 are described as “ball” seats having ball 100 (FIGS. 1-2), it is to be understood that the seats disclosed herein may be any type of seat known to persons of ordinary skill in the art. For example, the apparatus may be a drop plug seat, wherein the drop plug temporarily blocks the flow of fluid through the wellbore. Therefore, the terms “plug” and “plug member” as used herein encompass ball 100 as well as any other type of device that is used to temporary block the flow of fluid through the wellbore.

It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. For example, the seat may be used in connection with a ball, dart, or any other type of plug or plug member that is used to restrict or prevent fluid flow through the seat. Further, the fluid flow reduction members may be disposed on an inner wall surface of the tubular member. Accordingly, the invention is therefore to be limited only by the scope of the appended claims. 

1. A seat for receiving a plug member, the seat comprising: a tubular member having an inner wall surface defining a bore, the bore being divided into an upper portion and a lower portion; a seat disposed along the inner wall surface, the seat transitioning the inner wall surface from the upper portion to the lower portion; and a fluid flow reduction member, the fluid flow reduction member being disposed along the inner wall surface of the tubular member.
 2. The seat of claim 1, wherein the fluid flow reduction member comprises at least one groove disposed longitudinal to an axis of the seat, the at least one groove being disposed in the inner wall surface.
 3. The seat of claim 1, wherein the fluid flow reduction member comprises a plurality of grooves disposed longitudinal to an axis of the seat, the plurality of grooves being disposed in the inner wall surface.
 4. The seat of claim 1, wherein the fluid flow reduction member comprises at least one curved-shaped groove disposed in the inner wall surface.
 5. The seat of claim 4, wherein at least one of the at least one curved-shaped grooves comprises a spiral-shaped groove.
 6. The seat of claim 1, wherein the fluid flow reduction member comprises an insert, the insert comprising a sleeve having a sleeve inner wall surface and a sleeve outer wall surface, the sleeve outer wall surface being in engagement with the inner wall surface of the tubular member, the insert comprising at least one aperture disposed in the sleeve, the at least one aperture providing fluid communication between the sleeve inner wall surface and the sleeve outer wall surface.
 7. The seat of claim 1, wherein the fluid flow reduction member comprises an insert, the insert comprising a sleeve having a sleeve inner wall surface and a sleeve outer wall surface, the sleeve outer wall surface being in engagement with the inner wall surface of the tubular member, the insert comprising a plurality of apertures disposed in the sleeve, each of the plurality of apertures providing fluid communication between the sleeve inner wall surface and the sleeve outer wall surface.
 8. The seat of claim 7, wherein each of the plurality of apertures has an identical size and an identical shape.
 9. The seat of claim 7, wherein the sleeve outer wall surface comprises a recess in fluid communication with at least one of the at least one apertures.
 10. The seat of claim 1, wherein the fluid flow reduction member is disposed adjacent the seat.
 11. The seat of claim 1, wherein the fluid flow reduction member comprises an insert, the insert comprising a sleeve having a sleeve inner wall surface and a sleeve outer wall surface, the sleeve outer wall surface being in engagement with the inner wall surface of the tubular member and the sleeve inner wall surface comprising at least one groove disposed in the sleeve inner wall surface, at least one of the at least one grooves being disposed longitudinally relative to an axis of the sleeve.
 12. The seat of claim 11, wherein at least one of the at least one grooves extends from an upper end of the insert to a lower end of the insert.
 13. The seat of claim 11, wherein at least one of the at least one grooves extends does not extend from an upper end of the insert to a lower end of the inert.
 14. The seat of claim 1, wherein the fluid flow reduction member comprises an insert, the insert comprising a sleeve having a sleeve inner wall surface and a sleeve outer wall surface, the sleeve outer wall surface being in engagement with the inner wall surface of the tubular member and the sleeve inner wall surface comprising at least one curved-shaped groove disposed in the sleeve inner wall surface, the curved-shape groove.
 15. The seat of claim 14, wherein at least one of the at least one curved-shaped grooves comprises a spiral-shaped groove.
 16. A method of restricting fluid flow through a conduit disposed within a wellbore, the method comprising the steps of: (a) disposing a seat within a conduit; (b) running the conduit into a wellbore to a desired location; (c) flowing a fluid through the conduit and the seat, the fluid carrying a plug member toward the seat, the fluid flowing through the conduit above the seat at a first velocity; (d) flowing the fluid through a fluid flow reduction device disposed above the seat, the fluid flowing through the fluid flow reduction device at a second velocity, the second velocity being slower than the first velocity; and then (e) landing the plug member on the seat at a plug member velocity that is slower than the first velocity.
 17. The method of claim 16, wherein during step (d), the fluid flows through the fluid flow reduction device in a substantially longitudinal direction.
 18. The method of claim 16, wherein during step (d), the fluid flows through the fluid flow reduction device in a curved direction.
 19. The method of claim 16, wherein during step (d), the fluid flows out of an inner bore of the fluid flow reduction device by flowing through a first aperture disposed in a wall of the fluid flow reduction device.
 20. The method of claim 19, wherein after the fluid flows out of the inner bore of the fluid flow reduction device through the first aperture, the fluid flows into the inner bore of the fluid flow reduction device by flowing through a second aperture disposed below the first aperture. 